Custom steps adjustment in Marlin

Hey guys, I'm currently building an SLA 3D printer (I already have V1 prototype working) and I am looking at a way to make a galvo type printer out of stepper motors. I would like to know if it's possible to have variable steps/mm depending on the position it is. I don't know what type of code Marlin firmware use so maybe someone can help me out. I was thinking of something like this for the steps/mm section in the configuration.h file.

if (0<=POSITION_X<1)
#define DEFAULT_AXIS_STEPS_PER_UNIT {10,10,200.0*8/3,760*1.1}
elseif (1<=POSITION_X<2)
#define DEFAULT_AXIS_STEPS_PER_UNIT {11,11,200.0*8/3,760*1.1}
elseif (2<=POSITION_X<3)
#define DEFAULT_AXIS_STEPS_PER_UNIT {12,12,200.0*8/3,760*1.1}
elseif (3<=POSITION_X<4)
#define DEFAULT_AXIS_STEPS_PER_UNIT {13,13,200.0*8/3,760*1.1}

etc....

I would calculate the steps needed to have the good laser deplacement using a geared stepper motor with a 90:1 or something ratio.

Thanks

I forgot to join this picture to help comprehension of my problem.

Nobody know if something like this can be done in the marlin firmware? Does the microprocessor can understand terms like cosine, sine and Tan?

Quote
PierreYves.Pepin
Nobody know if something like this can be done in the marlin firmware? Does the microprocessor can understand terms like cosine, sine and Tan?

it can't be done in the current version, with some modifications it should be possible to do what you want,

the other option you could explore is to write a post processor that changes the gcode accoringly

Edited 1 time(s). Last edit at 09/23/2014 07:19PM by thejollygrimreaper.

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What kind of modifications would be needed? Does anyone could possibly make these changes? I could maybe pay for the changes to be made if these are serious modifications.

it would need to be in the kinematics code somwhere, the best place for a feature request would be on the github for marlin MArlin github

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